1. Field of the Invention
The present invention relates to energy conversion systems for converting solar radiation to electrical energy and more particularly to a dome-enclosed thin-film photovoltaic array on a stretched membrane that is self-powered to track the solar radiation.
2. Description of the Prior Art
It is well known to use a photovoltaic array in an energy conversion system that converts solar radiation to electrical energy. Photovoltaic cells in a photovoltaic array generate an electromotive force upon exposure to solar radiation causing current to flow in a circuit that includes the photovoltaic array.
The photo-voltaic cells are usually delicate crystal structures, especially those used in thin-film, photovoltaic arrays. Ideally, direct outside exposure of the photovoltaic array to solar radiation will provide optimal energy conversion. However, it is usually advisable to protect the photovoltaic (hereinafter referred to as PV) array from weather hazards such as hail, which can cause substantial damage to a PV array.
A known method of protecting PV arrays is to encapsulate them in an epoxy resin or other suitable material that is transparent to solar radiation. The encapsulation should be sufficiently strong to withstand weather hazards, such as hail storms, and prevalent wind forces. However, in obtaining the necessary encapsulation protection for the PV array some degradation in radiation transmissibility to the PV array occurs. The PV array is also usually mounted on a structure having a relatively sturdy construction to meet any prevailing wind load requirements.
Since the position of the sun relative to the PV array is one of continuous change it is well known to use a tracking apparatus to continuously orient the PV array or optimal exposure to solar radiation. The tracking apparatus must be powerful enough to overcome any wind loads on the PV array and the mounting structure and to overcome the inertia of such structure itself. Therefore, a suitable drive mechanism for the tracking system would be expected to function under prevailing wind loads and is thus likely to be quite robust and costly and to have a relatively high power consumption. The relatively high level of power consumption needed by the drive system detracts from the usable energy generated by the PV array.